Finite temperature calculations on spin correlation functions of the Haldane gap compound CsNiCl3CsNiCl3

We present the finite temperature calculations on the spin correlation functions of the Haldane gap compound CsNiCl3CsNiCl3. Based on the coupled-chain theory, two methods are used to do the calculations: the large-NN expansion and the Ginzburg–Landau approach. The comparisons with the inelastic neutron-scattering experiments are discussed.